A conventional electric contactor (an electromagnetic relay) including a movable contact contacting a fixed contact and being separated from the fixed contact is disclosed in, e.g. Japanese Patent Laid-Open Publication No. 10-308152. In the electric contactor disclosed in this document, a movable core (a movable core) causes a plunger (a movable shaft) to move in an axial direction as to cause the plunger to move a contact plate (a movable contact element) from a retracted position to an actuating position in the axial direction, thereby allowing the contact plate to contact a head (the fixed contact) of a terminal at the actuating position. The electric contactor disclosed in this document includes a lateral wall of a separation plate for reducing movement of foreign matter. The lateral wall described in this document is fixed on an inner side surface of a cover facing backward at the communication part between front and rear compartments of the cover.